Myelin water fraction mapping using relaxation spectra from steady-state gradient echo imaging with partial RF spoiling

A new approach for myelin water fraction (MWF) mapping is presented, based on gradient echo signals with small RF spoiling phase increments. Partially spoiled gradient echo data with 20 different phase increments (||20^) were efficiently acquired with a custom skipped-CAIPI 3D-EPI sequence. The data is well-suited for a novel joint-fitting approach of T₁- and T₂-spectra, from which high-quality whole-brain MWF maps are derived. MWF-maps show qualitatively good agreement with published data in the white matter (WM). Additionally, the approach seems to provide robust estimates in regions with small MWF, such as the gray matter (GM).